1. Field of the Invention
The present invention relates to hydrogen surface-treated graphene, and a formation method thereof and an electronic device including the same.
2. Discussion of Related Art
Graphene is a flat single-layer sheet formed of carbon atoms via sp2 bonds, a structure of which may be found in a pattern in which the carbon atoms are staked in a hexagonal crystal lattice. Therefore, graphene has a basic structure forming materials consisting of carbon atoms, such as graphite, carbon nanotubes, and fullerenes in the form of a buckyball. Also, graphene shows completely different properties than the carbon nanotubes in which carbon atoms are connected in a tubular geometry because of the structural difference. Graphene has emerged as the most promising material since it has an extensive range of advantages such as mechanical and electrical characteristics which the carbon nanotubes have, and also shows peculiar physical properties which two-dimensional materials have.
Carbon allotropes formed mainly via covalent bonds have physical properties as determined according to a linear combination mode for the wave functions of the four outermost electrons. Most of solids formed via covalent bonds have the maximum probability distribution of finding electrons between the atoms. One representative example of the carbon allotropes is diamond.
However, only the linear combinations of the three outermost electrons in graphene participate in formation of strong covalent bonds between carbon atoms to form a hexagonal network plane, and the wave functions of the remaining outermost electrons are present in a pattern perpendicular to the plane. The state of electrons which are parallel to the plane to participate in formation of strong covalent bonds is referred to as a σ-orbital, and the state of electrons perpendicular to the plane is referred to as a π-orbital. The wave functions of electrons near the Fermi level determining the physical properties of graphene are composed of linear combinations of π-orbitals.
In recent years, many researchers have paid attention to the fact that graphene shows zero-band gap characteristics due to the hexagonal network structure of graphene, the structure of two triangular sub-lattices, and a thickness corresponding to the size of one atom. Because of the zero-band gap characteristics, however, graphene has a problem in that it has limited applications to metal conductive films or wires in use for electronic devices.
Ardent research is being conducted recently on controlling a band gap of graphene. Also, much research is being conducted on controlling a band gap using a method of forming graphene in a nano-ribbon or nano-pattern and a method of applying an electric field to a substrate. However, the results of research on accurately controlling a band gap of graphene and search on methods of accurately controlling a band gap of graphene are not published so far.